As a part of feasibly study. I need to choose between Android or iOS for integrating it with an embedded system.
Basically, that embedded system will have an AVR or a PIC Microcontroller. I want to establish a communication between a mobile and that particular system.
Need some wireless technology for communication (bluetooth,wifi,internet etc..)
Micro Controllers have communication ports like UART, USART etc..
It really depends on the kind of communication you need.
I particular, if you have a normal WIFI connection and your controller can work with receiving & sending your data via wifi, you may go iOS or Android.
If however you need some kind of free format serial communication, you need to go Android, serial cable via USB.
recarding other factors, I guess it really is just a personal taste issue.
Could you give more info on how & what needs to be communicated and what kind of communication device you have between your phone and the device itself.
Not sure if this is similar to what you have in minde, but you might look at this: http://www.arduino.cc/ being probably the best known example in this context.